Domestic air source and cold callers

[minimutly]

So, no domestic install good news then - thought as much. I will report back next April...
Sorry @brewdexta , posts crossed - so there is a good news install. Nice to hear. Any info on running costs?

 

[brewdexta]

So, no domestic install good news then - thought as much. I will report back next April...
Sorry @brewdexta , posts crossed - so there is a good news install. Nice to hear. Any info on running costs?

My SiL may have some figures but it's hardly domestic, although the farmhouse and their daughter's cottage is also on the same or similar system. They do need more monitoring tools installed but I'm reticent to do it as i will be getting call outs, they are not overly technical.

Interestingly, I can hardly hear the air source pump fans when I'm there. Partially because I'm getting a bit mutton Jeff as I get older but even so, not really noticeable and the farm is in the middle of nowhere so noises standout more.

 

[Kayos]

Hardly relevant @Kayos ? We are talking domestic here.

Frame of reference is just different

For domestic context, the last project I delivered was 740 properties so can add a few more digits to that number

 

[Dragnet]

Heat people not places. I don't think any of these cold-calling installers have any idea about building physics. I've done a successful heat pump installation based around low-temperature underfloor background heat, with radiant panels for smaller specific areas where sedentary activities would take place. People don't overheat in the active bits or freeze in the stationary ones. The central heating concept is a big problem to my mind and a massive efficiency issue. Burning fuel to heat water to heat air to heat us is an enormous efficiency loss over numerous transitions, mostly to very good insulators which have a high specific heat capacity.

I don't agree with the current method of using PVs as they are polluting to manufacture and it happens overseas where environmental and labour regulations can be rather less rigorously enforced. They are also impossible to re-use or recycle after their finite lifespan. The only reasonable thing I can consider is 'reduce, re-use, recycle', in that order, if one is seriously interested in doing one's bit. Capitalism has done a great job of convincing us that the solution to a problem is always a purchase, when adding more garbage to the eart is rarely a good idea. That gets latched onto by cowboys who sell things that are not suitable to those only 'guilty' of trusting another human.

The Swiss architect Werner Schmidt has some good experimental houses heated and powered by Stirling engines from focussed sunlight. Low-Tech Magazine has articles on experiments in the 1900s with Schottky-junction PVs, which have the potential to be less complex and actually recyclable into useable metal again; and lots on direct solar. If only the government would investigate these rather more radical, and more resilient technologies than ever more complex industries with a very long tail of manufacturing complexity and associated resource use.

 

[brewdexta]

We don't use heat pumps be cause when we put in underfloor heating in the farm 20+ years ago, the statement was designed for the temp output of gas boiler. If I had known about heat pumps then, I would have requested more loops and a higher density of pipes, pipe us cheap as chips.

So I'm wondering if some of the issues that people have are that they have been sold a pup, heat pumps for a UFH system sized for gas temperature output?

 

[minimutly]

Frame of reference is just different

For domestic context, the last project I delivered was 740 properties so can add a few more digits to that number

So break it down into install costs vs running costs per property?

 

[minimutly]

We don't use heat pumps be cause when we put in underfloor heating in the farm 20+ years ago, the statement was designed for the temp output of gas boiler. If I had known about heat pumps then, I would have requested more loops and a higher density of pipes, pipe us cheap as chips.

So I'm wondering if some of the issues that people have are that they have been sold a pup, heat pumps for a UFH system sized for gas temperature output?

Well all the installs I've seen have had new rads as well - you'd hope someone would have done the transfer calcs?
And to be fair I don't know yet if they've all been sold a pup - winter running will tell us. But maybe said companies are banking on milder and milder winters...

 

[willie.macleod]

We don't use heat pumps be cause when we put in underfloor heating in the farm 20+ years ago, the statement was designed for the temp output of gas boiler. If I had known about heat pumps then, I would have requested more loops and a higher density of pipes, pipe us cheap as chips.

So I'm wondering if some of the issues that people have are that they have been sold a pup, heat pumps for a UFH system sized for gas temperature output?

Have you ran the numbers yourself for a heatpump on your UFH pipe? The floor temp won't be different for heatpump or gas boiler as it is limited anyway by the surface coverings. More pipe would allow the system to respond quicker but if the building has reasonable insulation then even with less pipe it may still be within acceptable Watts/m2 limits.

 

[julianthegypsy]

Might be worth getting someone to have a look at that then - just a thought

It's a rented house. The "engineer " comes out once a year. He wouldn't give me a manual because "most of our callouts are from people who have played with it", and he reckoned everything was fine and I was getting £4 out for every £1 I put in and it's great. You can't argue with idiots. The airsource pump can only get to forty degrees tops. Fine for underfloor but useless for radiators and useless in a poorly insulated house. I can believe they work under under ideal conditions, but how its exchanging heat when the fan is blowing freezing air is beyond me. Ground source surely has to make more sense as its never going to be freezing metres below ground so there is some actual heat to exchange. I found the manual on the net in the end, which is why it's now set to heat water only unless it's freezing.

 

[brewdexta]

Have you ran the numbers yourself for a heatpump on your UFH pipe? The floor temp won't be different for heatpump or gas boiler as it is limited anyway by the surface coverings. More pipe would allow the system to respond quicker but if the building has reasonable insulation then even with less pipe it may still be within acceptable Watts/m2 limits.

My heating engineer did it. I have the original plans from when the UFH was installed. We do have quite a lot if insulation, but installed 20 years ago, I would double it now. For example, the walls are rubble filled stone, approx 300 yrs old. So I fixed 50mm kingspan/celotex backed plasterboard to the inside of all external walls. I would put 100mm in now, but I'm not going to retro fit it. I would rather wear an extra jumper

My heating engineer is pretty good at this stuff and he's a good friend. I trust his opinion, he is usually proved right.

We ended up with biomass instead, works fine. I may reconsider in the future, but use the two stoves as well as UFH.

 

[waddycall]

It's a rented house. The "engineer " comes out once a year. He wouldn't give me a manual because "most of our callouts are from people who have played with it", and he reckoned everything was fine and I was getting £4 out for every £1 I put in and it's great. You can't argue with idiots. The airsource pump can only get to forty degrees tops. Fine for underfloor but useless for radiators and useless in a poorly insulated house. I can believe they work under under ideal conditions, but how its exchanging heat when the fan is blowing freezing air is beyond me. Ground source surely has to make more sense as its never going to be freezing metres below ground so there is some actual heat to exchange. I found the manual on the net in the end, which is why it's now set to heat water only unless it's freezing.

That’s a pain. If the fan outside is blowing out freezing cold air it’s because the heat pump has taken the heat out of it. Can’t remember what air source COP are measured at but could be 7C air temp into outdoor unit.

 

[waddycall]

https://researchbriefings.files.parliament.uk/documents/POST-PN-0699/POST-PN-0699.pdf

 

[Kayos]

So break it down into install costs vs running costs per property?

The residents saved on average 40% on their previous bills

 

[Mikes]

We don't use heat pumps be cause when we put in underfloor heating in the farm 20+ years ago, the statement was designed for the temp output of gas boiler. If I had known about heat pumps then, I would have requested more loops and a higher density of pipes, pipe us cheap as chips.

So I'm wondering if some of the issues that people have are that they have been sold a pup, heat pumps for a UFH system sized for gas temperature output?

There will be very little difference in the design of a heat pump underfloor heating system and a boiler underfloor heating system as the limitations are the maximum temperature that the pipe will accept and the screed / floor covering maximum permissible temp. The upper limit for the PEX pipe is about 50 C so ideally suited for a heat pump flow which is probably about 45 C without any temperature reduction. When using a gas boiler as the heat source, the maximum flow temperature is limited at the underfloor heating manifold by either local mixing valves or direct boiler temperature control so that the maximum pipe temperature is not exceeded. The density of the pipes would be to suit the area heat loss and wouldn't vary between either source.

 

[not done it yet]

If 2000 people with all-electric houses, where an air-sourced heat pump has been installed, I would expect all of them to report enthusiastically re the system. Bound to be an improvement in efficiency. That result may be different from a different sub-set of installations.

Would I trust a survey by a pro ASHP supplier or advocate of the system? No, I would not. Just sayin’.

Same with marketing cold-callers. But a lot of people do believe what they are told without any further checks.

I’m not saying some, or even most get some improvement of economy, but at the present time I do wonder why that needs a five grand subsidy to encourage those, that are already requiring a new boiler, to change.

 

[gaz1]

Heat people not places. I don't think any of these cold-calling installers have any idea about building physics. I've done a successful heat pump installation based around low-temperature underfloor background heat, with radiant panels for smaller specific areas where sedentary activities would take place. People don't overheat in the active bits or freeze in the stationary ones. The central heating concept is a big problem to my mind and a massive efficiency issue. Burning fuel to heat water to heat air to heat us is an enormous efficiency loss over numerous transitions, mostly to very good insulators which have a high specific heat capacity.

actually its not with a stove you get a view as well as heat from the unit whilst also storing this heat within a hot water tank

the issue i have with wood stoves is there very poor on economy of the wood material that your burning

now a downdraft stove hits higher temps than you would get with just a normal wood stove

heating water for a radiator gives stored energy for a while whilst flash heat will disipate much quicker

now flash heat is useless unless your home is well insulated but it wont store this heat flash heat is like factory air blower heaters basically designed to heat the air fast but heating a home up is different

stirling engines have moved on alot compared to what they once was

solar panels are not recyclable but they can be used second hand in other installments until its output is well below its level so it does have second to 7th use depending on your system that you build it for

 

[julianthegypsy]

That’s a pain. If the fan outside is blowing out freezing cold air it’s because the heat pump has taken the heat out of it. Can’t remember what air source COP are measured at but could be 7C air temp into outdoor unit.

So when the temperature is around zero, it's useless, no?

 

[willie.macleod]

So when the temperature is around zero, it's useless, no?

It's not useless, it can still extract heat from the outside air well below freezing but the efficiency drops off and it needs to use direct electric heat to defrost itself on occasion as well.

 

[fizzy]

They are talking of installing a huge battery system in Yorkshire.

https://renews.biz/83517/banks-files-mega-battery-planning-application/

Will be the biggest in the World. 2.8gw/h - costing £750 million.
Current demand in the UK in winter reaches about 50gw/h - will be a heck of a lot more if they install all these heat pumps. Throw electric cars into the mix and where do they think all this power will come from?
Based on current usage with no increase in demand it would power Great Britain for 3 minutes and 30 seconds. What is the point? We can go 2 weeks with virtually no wind in Winter and solar is way down.

 

[Beeezer]

They are talking of installing a huge battery system in Yorkshire.

https://renews.biz/83517/banks-files-mega-battery-planning-application/

Will be the biggest in the World. 2.8gw/h - costing £750 million.
Current demand in the UK in winter reaches about 50gw/h - will be a heck of a lot more if they install all these heat pumps. Throw electric cars into the mix and where do they think all this power will come from?
Based on current usage with no increase in demand it would power Great Britain for 3 minutes and 30 seconds. What is the point? We can go 2 weeks with virtually no wind in Winter and solar is way down.

Another government folly….